\input pst-node.tex
%\input pst-eps.tex
\headline={}
\footline={}
\def\nmatrix{\vcenter\bgroup\hbox\bgroup\catcode`\&=4 $\psmatrix[rowsep=0.3ex,colsep=1.5ex]}
\def\endnmatrix{\endpsmatrix$\egroup\egroup}
\def\ndetmat{\hbox\bgroup$\delimiterfactor=1025\left\lvert\vcenter\bgroup\hbox\bgroup\catcode`\&=4 $\psmatrix[rowsep=0.3ex,colsep=1.5ex]}
\def\endndetmat{\endpsmatrix$\egroup\egroup\right\rvert$\egroup}
%\TeXtoEPS
$
\def\pa{\phantom{a_1}}
\psmatrix[rowsep=1ex,colsep=2ex]
	\pa & \pa & \pa & \pa & \pa & \pa &\pa \\
	\pa & a_1 & b_1 & c_1 & a_1 & b_1 &\pa \\
	\pa & a_2 & b_2 & c_2 & a_2 & b_2 &\pa \\
	\pa & a_3 & b_3 & c_3 & a_3 & b_3 &\pa \\
	\pa & \pa & \pa & \pa & \pa & \pa &\pa
\endpsmatrix
\psset{nodesep=1pt,linewidth=0.4pt}
\ncline{-}{1,1}{2,2}%
\ncline{-}{2,2}{3,3}%
\ncline{-}{3,3}{4,4}%
\ncline{-}{4,4}{5,5}
\ncline{-}{1,2}{2,3}%
\ncline{-}{2,3}{3,4}%
\ncline{-}{3,4}{4,5}%
\ncline{-}{4,5}{5,6}
\ncline{-}{1,3}{2,4}%
\ncline{-}{2,4}{3,5}%
\ncline{-}{3,5}{4,6}%
\ncline{-}{4,6}{5,7}
\psset{linestyle=dashed}
\ncline{-}{1,7}{2,6}%
\ncline{-}{2,6}{3,5}%
\ncline{-}{3,5}{4,4}%
\ncline{-}{4,4}{5,3}
\ncline{-}{1,6}{2,5}%
\ncline{-}{2,5}{3,4}%
\ncline{-}{3,4}{4,3}%
\ncline{-}{4,3}{5,2}
\ncline{-}{1,5}{2,4}%
\ncline{-}{2,4}{3,3}%
\ncline{-}{3,3}{4,2}%
\ncline{-}{4,2}{5,1}
$
%\endTeXtoEPS
\bye
